This disclosure relates to semiconductor processing. More particularly, the disclosed subject matter relates to an ion beam source for use in ion implantation equipment for semiconductor processing.
Ion implantation is commonly used for doping a semiconductor material at precisely controlled depths and dopant concentrations. An ion implanter generally includes an ion source to generate an ion beam, ion beam transport optics for accelerating the ion beam, and a process chamber where the ion implantation on a semiconductor wafer occurs. The ions are mostly positively charged. During ion implantation, the charged ion beam strikes the semiconductor wafers in the process chamber, resulting in a doped semiconductor wafer when the dopant ions diffuse into the wafer.
Meanwhile, the size of semiconductor wafers has gradually increased to improve throughput and reduce cost per die. For example, in the transition from 300 mm to 450 mm wafer size, the wafer area increases by 125%. The within wafer uniformity (WiWU) becomes more difficult to maintain in the more-than-double-sized wafer.